In the prior art there are a multiplicity of techniques and devices for modulating light, particularly light emanating from a laser. In some of the light modulating techniques and devices there are utilized photomultipliers. In the present invention a static crossed field photomultiplier is employed by using a gating electrode which is mounted in a position between the cathode and the rail electrode. The electrode is pulsed with a sinusoidal RF drive for the purpose of causing the cathode current to be either multiplied or diverted so as to cut off the flow of collector current. This permits the modulation of the current by shifting the cathode beam into and out of the dynode area where secondary amplification occurs.